1. Field of the invention:
This invention relates to a method of scraping off burrs left after formation of a golf ball of resin outer layer and a burr scraping machine for use in carrying out the above method.
2. Prior art:
In manufacturing golf balls, it has been inevitable that ring-like or dot-like burrs are generated along the equator part of each golf ball and such burrs have been scraped off with a sandpaper or a grindstone. However, some errors in diameter are unavoidable in manufacturing golf balls on the mass production basis and therefore if grinding is effected on the basis of the fixed measurement, errors are caused in scraping width, with the result of deterioration of finished goods value and reduction in the rate of good quality articles. Thus, automation of burr scraping by grinding was difficult.
As the step of solving the above problem, the invention made by the present inventor entitled "Method and apparatus for removing burrs of gold balls" (Japanese Patent Application Laying Open Publication Gazette No. 60-232861) is already known. According to this invention, a disc-like grindstone which rotates positively and a pair of upper and lower profiling rollers which are alongside the equator part of a golf ball are held in the fixed position and while the golf ball is being rotated as it is held by an upper and a lower grippers, the equator part of the golf ball is pushed against profile rollers so that it makes contact with the grindstone. By this method, even if there exist some errors in the diameter of golf balls of rubber outer layer, only burrs can be scraped off without impairing the degree of true circle of golf balls and burr removing operation can be carried out at high efficiency. According to this method, burrs are scraped off by grinding, while a grindstone which is rotating positively is made to contact with a rubber golf ball and therefore this method is effective for golf balls or rubber outer layer but is not effective for golf balls of resin outer layer (for example, golf balls of plastic outer layer) because heat is generated by contact of a rotating grindstone with a golf ball and as a result, a golf ball of resin outer layer is deformed and complete scraping off of burrs cannot be done.